Damping mechanisms for coherent oscillations of axions
It has been proposed that the ''mass turn-on'' of the axion field in the early Universe could have set that field into a large-amplitude coherent oscillation. We give here a general analysis of damping mechanisms for field oscillations of this nature which are operative during an era of ''mass turn-on.'' A thermal-damping mechanism is analyzed in detail. Order-of-magnitude estimates indicate that the mechanism could possibly be important for axions if the mass turn-on rate is very large near the QCD temperature. If part of the mass turn-on occurs in association with a phase transition, a similar damping mechanism due to phase nonequilibria could be operative. Furthermore, supercooling could lead to a very effective damping mechanism. In addition, phase separation could result in scattering of the axions and destruction of their coherence. Other damping mechanisms of a more mechanical nature are also analyzed. We conclude that the upper limit of approx.10/sup 12/ GeV for the vacuum expectation value associated with the spontaneous breaking of Peccei-Quinn symmetry: previously derived from arguments concerning cosmological overproduction of coherent axions: should not be considered as firm.
- Research Organization:
- Department of Physics, University of British Columbia, Vancouver, British Columbia, Canada V6T 2A6
- OSTI ID:
- 5513944
- Journal Information:
- Phys. Rev. D; (United States), Vol. 32:4
- Country of Publication:
- United States
- Language:
- English
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71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AXIONS
MASS
UNIVERSE
COHERENT PRODUCTION
COHERENT SCATTERING
CP INVARIANCE
DAMPING
HAMILTONIANS
QUANTUM CHROMODYNAMICS
SCALAR FIELDS
SYMMETRY BREAKING
WKB APPROXIMATION
BOSONS
ELEMENTARY PARTICLES
FIELD THEORIES
GOLDSTONE BOSONS
INVARIANCE PRINCIPLES
MATHEMATICAL OPERATORS
PARTICLE PRODUCTION
POSTULATED PARTICLES
QUANTUM FIELD THEORY
QUANTUM OPERATORS
SCATTERING
645201* - High Energy Physics- Particle Interactions & Properties-Theoretical- General & Scattering Theory
645400 - High Energy Physics- Field Theory
640106 - Astrophysics & Cosmology- Cosmology